I now know a much easier way to make the draft stopper (which I will be using on the final draft stoppers) and maybe you can extend or adapt my technique to your use:
1. measure the distance from ridge line to the straight line connecting corner ring to corner ring (or just use the distance to the spreader bar which will probably be pretty close to the same thing) with hammock empty. This distance will be smaller when you get into the hammock, at least mine is since my spreader bars swing up towards the ridge line when I get in - the forces on the arc cut webbing guarantee that. So measure when empty as that will be the longer measure which you have to fit. Since you know the spreader bar length or the distance from corner ring to corner ring, that gives you the dimensions of the triangular shape from the corner rings to the ridge line. That part is then easy to fit, just allow for hems or bias tape whichever you use.
2. You already know the length of the fabric from corner to corner on the side of the hammock, call this length p/2 (see below), so you know the length of the bottom edge of the fabric for the side piece and all you really need is the shape. The easiest way to fit the needed shape is to use either a circle or ellipse. The ellipse will fit the shape of the hammock when occupied better than the circle, so make an ellipse with the required arc length from semi-minor axis to semi-minor axis - you know the length of the semi-minor axis already - 1/2 the distance from corner ring to corner ring, so all you need is the length of the semi-major axis which is given approximately by:
a**2 = ((p/pi)**2)/2 - b**2
a == length of semi-major axis == distance from straight line connecting corner rings to bottom of hammock fabric,
p == circumference of ellipse, or twice the length of the hammock fabric from corner to corner,
b = length of semi-minor axis == 1/2 corner ring to corner ring distance,
Compute and draw the appropriate ellipse and you have the bottom portion of the side piece.
Make a pattern out of heavy paper or cardboard with the triangle and elliptical bottom and have someone hold it to the hammock side while you are in it or have someone get while you do that. See how it fits.
It might even be easier to forget the whole elliptical part and draw the bottom curved shape directly from the hammock while your assistant is in the hammock. I seriously doubt that the bottom shape will change much depending on the occupant. If I had an assistant, I would go this route.
3. I then have a piece that is sewn to the bottom portion of the above piece and fits under the hammock from hammock end to hammock end. It forms the "cup" that seals the draft stopper. This piece is very simple to make - simply lay your hammock on the floor spread out on the needed fabric with the side of the hammock aligned on the edge of the fabric. Decide on the width of the bottom "band", trace the arcs on each end down to the width of the band (allowing for hems or bias tape) and then draw the straight line from arc to arc (again allowing for hems or bias tape). That gives the band to exactly fit the underside of the side of the hammock. Sew to the end piece cut in 1 and 2 above.
The Bridge hammock is really easy to fit
Hem or add bias tape to edges, sew on tie outs and it is done.
Now for the bug netting, all you really need is steps 1. and 2. Note that if you use spreader bars on the head side and foot side of differing length as I do, then the side pieces are going to be different. I suppose you could make both to fit the head side and the foot side will just have a small amount of excess material which then means you don't have to be concerned with head and foot sides of the bug netting.